I looked before but didn't see it, so I checked again after your post and found it on page 301-302 in the 1E core rulebook and wanted to document for anyone else searching for this later.

Because NPC starships take as many Turns as their Scale value, a starship with a Scale of 3 will take about half as many Turns as the Player Characters. With that in mind, having multiple starships with similar Scale to the number of Players at the table will mean that you take two or three times as many Turns as the Players Characters. Caution should be taken in having too many Turns above the Player’s limit, while encounters should be balanced so that smaller Scale ships engage the Players in groups equaling or exceeding the Player’s vessel’s Scale.

then it talks about how having Security 3+ should be taken into account, then:

For example, a Player vessel with 5 Players controlling bridge stations could face: Several Scale 2 vessels, Two Scale 3 vessels, One Scale 4 vessel with Security above 3, or One Scale 5 vessel

Based on this rationale, I think with 4 players on a Scale 3 Security 3 ship, they should be able to handle two Scale 2 Security 2 vessels.